Re: [PATCH v2 00/15] KVM: arm64: nv: FPSIMD/SVE, plus some other CPTR goodies

[Marc Zyngier <maz@kernel.org>]

On Thu, 13 Jun 2024 21:17:41 +0100,
Oliver Upton <oliver.upton@linux.dev> wrote:
> 
> As discussed, here's the combined series of Marc + I's patches that
> implement all the trap forwarding / merging logic required to observe
> the L1 CPTR configuration when running an L2 guest.
> 
> Like before, this was tested on Neoverse-V2 with L0, L1, and L2 running
> fpsimd-test and sve-test on top of one another.
> 
> v1 [1] -> v2:
>  - Grab Marc's CPTR trap patches [2]
>  - Avoid taking two traps when L1 accesses ZCR_EL2 while the host owns
>    FP regs. The fast path will now load the FP regs and forward the
>    sysreg trap to the slow path for complete handling.
>  - Add a comment describing the above behavior (Marc)
>  - Avoid the use of guest_hyp_*_traps_enabled() in
>    __activate_cptr_traps() for better codegen (Marc)
>  - Document the reason for only testing bit[0] of CPTR_EL2.xEN when
>    folding L1 traps into the hardware CPTR value.
>  - Add a helper for synthesizing SVE traps, rather than open-coding the
>    ESR value in access_zcr_el2()
> 
> [1]: https://lore.kernel.org/kvmarm/20240531231358.1000039-1-oliver.upton@linux.dev/
> [2]: https://lore.kernel.org/kvmarm/20240604130553.199981-1-maz@kernel.org/
> 
> Jintack Lim (1):
>   KVM: arm64: nv: Forward FP/ASIMD traps to guest hypervisor
> 
> Marc Zyngier (4):
>   KVM: arm64: nv: Handle CPACR_EL1 traps
>   KVM: arm64: nv: Add TCPAC/TTA to CPTR->CPACR conversion helper
>   KVM: arm64: nv: Add trap description for CPTR_EL2
>   KVM: arm64: nv: Add additional trap setup for CPTR_EL2
> 
> Oliver Upton (10):
>   KVM: arm64: nv: Forward SVE traps to guest hypervisor
>   KVM: arm64: nv: Load guest FP state for ZCR_EL2 trap
>   KVM: arm64: nv: Load guest hyp's ZCR into EL1 state
>   KVM: arm64: nv: Handle ZCR_EL2 traps
>   KVM: arm64: nv: Save guest's ZCR_EL2 when in hyp context
>   KVM: arm64: nv: Use guest hypervisor's max VL when running nested
>     guest
>   KVM: arm64: nv: Ensure correct VL is loaded before saving SVE state
>   KVM: arm64: Spin off helper for programming CPTR traps
>   KVM: arm64: nv: Honor guest hypervisor's FP/SVE traps in CPTR_EL2
>   KVM: arm64: Allow the use of SVE+NV
> 
>  arch/arm64/include/asm/kvm_emulate.h    |  55 +++++++++
>  arch/arm64/include/asm/kvm_host.h       |   7 ++
>  arch/arm64/include/asm/kvm_nested.h     |   5 +-
>  arch/arm64/kvm/arm.c                    |   5 -
>  arch/arm64/kvm/emulate-nested.c         |  91 ++++++++++++++
>  arch/arm64/kvm/fpsimd.c                 |  22 +++-
>  arch/arm64/kvm/handle_exit.c            |  19 ++-
>  arch/arm64/kvm/hyp/include/hyp/switch.h |  24 +++-
>  arch/arm64/kvm/hyp/vhe/switch.c         | 156 ++++++++++++++++++++----
>  arch/arm64/kvm/nested.c                 |   3 +-
>  arch/arm64/kvm/sys_regs.c               |  38 ++++++
>  11 files changed, 380 insertions(+), 45 deletions(-)

Patches 1,5,7 may require some very minor rework, but they are
functionally correct AFAICT. Patches 3,12-14 do not warrant my RB.

For patches 1-2,4-11,15, and with the bisection issue fixed:

Reviewed-by: Marc Zyngier <maz@kernel.org>

	M.

-- 
Without deviation from the norm, progress is not possible.